“It ain’t worth it,” Bisping said. “What else am I going to do? I won the belt, I’ve had tons of wins. I’ve done everything I set out to achieve.

“What’s the point of flogging a dead horse? Not that I’m a dead horse, but what’s the point? … I’ve used my platform to open other doors. You’ve got to know when to walk away. I’m almost 40 years old – the time is now.”

As recently as a few weeks ago, Bisping (30-9 MMA, 20-9 UFC) was still on the fence about whether to compete one last time or call it quits. A third bout against rival Luke Rockhold appeared to be the frontrunner for his final opponent. Bisping said he would jump on a fight at light heavyweight if former middleweight champ fought Alexander Gustafssson for an interim title.

Bisping also welcomed a bout with UFC star Nick Diaz, who recently had been cleared to compete after serving a USADA suspension.

Very recently, however, both of those options have suffered major issues outside the octagon. Rockhold sustained a leg injury that will keep him from fighting Gustafsson, and Diaz was recently arrested and charged with felony domestic battery.

It’s unclear whether those recent developments influenced Bisping’s decision, but he said he’d realized his time in the sport is up.

“It’s been a long journey – in 2003, I started training,” he said. “So 15 years as a professional fighter, 12 or 13 years in the UFC. You can’t do it forever. I’ve done it for a long time, and of course I’ve got issues with my eye. After the (Kelvin) Gastelum fight, I started having issues with my good eye, which I’ve never spoken about before.”

Bisping’s agent, Audie Attar, released a statement to MMAjunkie about his star client’s retirement.

“Congrats to Michael on a Hall of Fame career,” Attar said. “‘The Ultimate Fighter’ winner, two-time ‘Ultimate fighter’ coach, winningest fighter in UFC history and first British UFC Champion in history. I’ve been honored to work with Michael toward the championship years and have watched him fight through trials and tribulations as he was a perennial title contender, ultimately reaching the sport’s greatest achievement by winning a UFC championship.

“Through all that, he has achieved the one thing I’m most proud of – how hard he fought for his family’s future, risking his life on the line each time he stepped into the octagon. I am proud to call Michael a client, but more importantly a dear friend. Now it’s time for Michael to achieve greatness in the next phase of his professional career. The future looks bright, Mr. Bisping. Thank you for all that you’ve done for our sport!”

In 2013, Bisping suffered a detached retina that forced him to have surgery. He said his initial eye injury was the result of taking a head kick from Vitor Belfort when they faced off in January of that year. The surgery prompted him to withdraw from a headliner against Mark Munoz at UFC Fight Night 30 in his hometown of Manchester, England.

Bisping has spoken several times about the physical damage he has sustained in more than a decade of combat sports experience. Still, after back-to-back losses, he hoped to make one last walk to the cage in his native Britain.

At one point, he was in negotiations to rematch Rashad Evans at UFC Fight Night 127 in March. But he later announced he wouldn’t compete, and Evans said Bisping and the UFC couldn’t come to terms on a contract.

Bisping retires with a record 29 UFC appearances, achieving a 20-9 record inside the octagon. He shocked the world in 2016 with an upset knockout of Rockhold to win the UFC middleweight title, an accolade that repeatedly eluded him after losses in three title eliminator fights.

This past November, Bisping lost the middleweight title to Georges St-Pierre, and a quick turnaround against Kelvin Gastelum ended in a first-round knockout.

Although his role as a perpetual heel chafed many MMA fans, Bisping’s accomplishments inside the octagon are many: His 20 victories in UFC competition are tied with St-Pierre and Donald Cerrone for most in company history; 16 victories in UFC middleweight competition are most in divisional history: and seven knockout victories in UFC middleweight competition are tied for second most in divisional history behind ex-champion Anderson Silva, whom he beat just three months before winning the title.

Bisping first made his mark by winning “The Ultimate Fighter 3” and quickly rose to become one of the biggest stars in the promotion.